近115a中亚干湿气候变化研究

Characteristics of the Dry/Wet Climate Change in Central Asia in Recent 115 Years

利用1901—2015年东英吉利大学气候研究中心(CRU)提供的月平均气温、降水、潜在蒸散量以及西班牙比利牛斯生态研究所(IPE-CSIC)创建的12个月尺度的标准化降水蒸散指数SPEI_(12),对中亚地区近115 a气候要素进行综合分析,并探究中亚地区干湿气候的时空变化。结果表明,中亚地区年平均气温的空间分布表现为东、西部高,中部低,全区呈显著增温趋势,其气候倾向率为0.15℃·(10 a)^(-1);年降水量表现为中南部多,东、西部少,除北部哈萨克斯坦平原地区外其他区域降水量均为增多趋势;全区年潜在蒸散量远大于年降水量,且与地形及下垫面联系密切,表现为东西部沙漠地区大,中部山区相对较小的特征;考虑水热平衡的干湿指数SPEI_(12)在哈萨克平原为弱的减小(略变干)趋势,其他区域呈增大(变湿)趋势。利用旋转经验正交函数(REOF)对SPEI_(12)进行分解得到6个子区域,各分区气温突变时间东边早于西边,降水量西边显著增多早于东边,且SPEI_(12)突变时间西边早于东边。利用集合经验模分解(EEMD)对SPEI_(12)和降水量不同时间尺度及其变化周期进行分析,得到SPEI_(12)存在准14 a的显著振荡周期,降水量存在准3 a、14 a的显著振荡周期。

Based on the monthly mean temperature,precipitation and potential evapotranspiration data provided by CRU and the standardized precipitation evapotranspiration data with 12 months scale(SPEI 12)from IPE-CSIC during 1901-2015,the climatic factors in recent 115 years were comprehensively analyzed and the spatial-temporal pattern of dry/wet climate change was explored in Central Asia.The results show that the spatial distribution of annual mean temperature in Central Asia presented warmer in east and west regions but colder in the middle,and it showed a significant warming trend in the whole region and its climate tendency rate was 0.15℃·(10 a)-1.For annual precipitation,it was more in central and south regions and less in the east and west regions,and it was increasing in most regions except the Kazakhstan Plain in the northern Central Asia.The annual potential evapotranspiration in the whole region was much larger than annual precipitation,which was closely related to topography and underlying surface,and it was characterized by larger in the east and west desert area and relatively smaller in the central mountainous region.The dry/wet index SPEI 12 considering the water-heat balance showed a weaker decreasing trend in the Kazakh plains,which indicated the area became slightly dry,while in other areas it presented an increase trend,which indicated the areas became wet.The SPEI 12 was decomposed into six sub-regions by using the rotated empirical orthogonal function(REOF),and the abrupt change of temperature was earlier in the east than that in the west for each subarea,and precipitation in the west increased significantly earlier than that in the east,and the mutation time of SPEI 12 in the west was earlier than that in the east.Based on the ensemble empirical mode decomposition(EEMD),the variation period of SPEI 12 and precipitation were analyzed at different time scales.SPEI 12 had a significant oscillation period of quasi-14 years and precipitation had a significant oscillation period of quasi-3 years and 14 years.